[Wikipedia: Detail of a scene in the bowl of the letter 'P' with a woman with a set-square and dividers; using a compass to measure distances on a diagram. In her left hand she holds a square, an implement for testing or drawing right angles. She is watched by a group of students. In the Middle Ages, it is unusual to see women represented as teachers, in particular when the students appear to be monks. She is most likely the personification of Geometry, based on Martianus Capella's famous book De Nuptiis Philologiae et Mercurii, [5th c.] a standard source for allegorical imagery of the seven liberal arts. Illustration at the beginning of Euclid’s Elementa, in the translation attributed to Adelard of Bath.]